Optical projector module, three-dimensional image sensing apparatus, and method of sensing

ABSTRACT

An optical projector module to establish distance to target object in a field of view for three dimensional image acquisition purposes includes a printed circuit board, point light sources mounted on the printed circuit board to emit a plurality of light beams, a lens unit apart from the plurality of point light sources, and a distance adjusting unit connected to the lens unit. A memory storage device is also included. The lens unit comprises separated lenses, the adjusting unit can adjust distances between the lenses of the lens unit, and light beams with a number of light spot patterns can accordingly be projected. Previously-captured images in the memory storage device can be referred to in seeking target objects in the field of view and light beams in different spot-concentrations on or around the target object enable calculations for the capture of images in three dimensions of the target object.

FIELD

The subject matter herein generally relates to three-dimensional imagesensing.

BACKGROUND

Depth of a target object in a field of view can be obtained via anoptical projector module. Such optical projector module can project afixed number of light beams on a target object, but it is difficult todetermine facial features of a human in the field of view.

Therefore, there is room for improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by wayof embodiments only, with reference to the attached figures.

FIG. 1 shows architecture of an embodiment of a three-dimensional imagesensing apparatus.

FIG. 2 is a cross-sectional view of an optical projector module in thethree-dimensional image sensing apparatus in FIG. 1.

FIG. 3 is a cross-sectional view of a lens unit in the optical projectormodule in FIG. 2, the lens unit comprising three lenses.

FIG. 4 is a schematic diagram of a first light point density generatedby the optical projector module in FIG. 2.

FIG. 5 is a schematic diagram of a second light point density generatedby the optical projector module in FIG. 2.

FIGS. 6-7 are schematic diagrams of light sources arranged on a printedcircuit board in a array, the array being divided into a plurality ofsub-arrays, each sub-array being independently controlled

FIG. 8 is an isometric view of a three-dimensional image sensingapparatus in accordance with one embodiment.

FIG. 9 is a flowchart of a method for three-dimensional sensing systemapplied to the three-dimensional image sensing device in FIG. 2.

FIG. 10 is another flowchart of a method for a three-dimensional sensingsystem.

FIG. 11 is a schematic diagram of a first projection of the opticalprojector module of FIG. 2 to a target area.

FIG. 12 is a schematic diagram of a second projection of the opticalprojector module to a target area.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein can be practiced without these specificdetails. In other instances, methods, procedures, and components havenot been described in detail so as not to obscure the related relevantfeature being described. Also, the description is not to be consideredas limiting the scope of the embodiments described herein. The drawingsare not necessarily to scale, and the proportions of certain parts maybe exaggerated to illustrate details and features of the presentdisclosure better. The disclosure is illustrated by way of embodimentsand not by way of limitation in the figures of the accompanyingdrawings, in which like references indicate similar elements. It shouldbe noted that references to “an” or “one” embodiment in this disclosureare not necessarily to the same embodiment, and such references mean “atleast one.”

Several definitions that apply throughout this disclosure will now bepresented.

The term “substantially” is defined to be essentially conforming to theparticular dimension, shape, or other feature that the term modifies,such that the component need not be exact. For example, “substantiallycylindrical” means that the object resembles a cylinder, but can haveone or more deviations from a true cylinder. The term “comprising,” whenutilized, means “including, but not necessarily limited to”; itspecifically indicates open-ended inclusion or membership in theso-described combination, group, series, and the like. The references “aplurality of” and “a number of” mean “at least two.”

FIG. 1 illustrates a three-dimensional image sensing apparatus 100. Thethree-dimensional image sensing apparatus 100 includes an opticalprojector module 11, a microphone module 12, a sound encoding module 13,a rotation module 14, an image acquisition module 15, an imageprocessing unit 16, an arithmetic unit 17, and a memory unit 18.

As shown in FIG. 2, the optical projector module 11 is configured togenerate a structured light pattern and includes a lens barrel 110, aprinted circuit board 111, at least one light source 112, an opticalmember 113, a light spots generating unit 114, a lens unit 115, and anadjusting unit 116. The lens barrel 110 is mounted on the printedcircuit board 111. The optical member 113, the light spots generatingunit 114, and the lens unit 115 are mounted in the lens barrel 110. Inthe embodiment, the at least one light source 112 includes a pluralityof light sources 112 emitting light, and the plurality of light sources112 are mounted on the printed circuit board 111. The light source 112also can be a laser to emit visible light, non-visible light such asinfrared, ultraviolet, and so on. In the embodiment, the light source112 is a vertical cavity surface-emitting laser (VCSEL).

The optical member 113 is a convex lens. The optical member 113 isdisposed in a light path of the light sources 112 for receiving lightbeams emitted from the light sources 112 and collimating the lightbeams. For example, the divergent light beams emit by the VCSEL can becollimated into parallel beams, to ensure that the beam energy emittedby the light source 112 is more concentrated.

The light spots generating unit 114 can be a diffraction optical element(DOE) disposed in a light path of the optical member 113 for expandingor splitting the light beams from the optical member 113, and thenforming structured light pattern. In one embodiment, a number of thelight beams emitted by the at least one light source 112 may be 70. Thatis, the number of light beams transmitted to the spot generating unit114 via the optical member 113 is 70. The light spots generating unit114 expands or splits the light beams at a certain magnification. In oneembodiment, the magnification can be 50 times; thereby, a number of thelight beams B expanded or split from the light spots generating unit 114is 3500, and then the light beams B are projected to a target areathrough the lens unit 115, to produce 3500 light spots on a target area.In other embodiments, there will be some overlap of light spots,resulting in the number of the light spots being less than 3500.

In other embodiments, the light spots generating unit 114 is not limitedto a light spots generating unit (DOE), a grating or a combination ofvarious optical elements may be used for diverging or splitting lightbeams.

Referring to FIG. 3, the lens unit 115 is disposed in a light path ofthe light spots generating unit 114 and spaced apart from the lightspots generating unit 114. The lens unit 115 receives the light beams Bthat are diverged or split by the light spots generating unit 114. Thelens unit 115 includes a plurality of lenses, and the plurality oflenses are spaced apart from each other. In the embodiment, the lensunit 115 includes three lenses: a first convex lens L1, a second convexlens L2, and a concave lens L3. The first convex lens L1 is disposedadjacent to the light spots generating unit 114 to receive light beamsB. The second convex lens L2 is disposed on one side of the first convexlens L1 away from the light spots generating unit 114. The concave lensL3 is disposed between the first convex lens L1 and the second convexlens L2. In other embodiments, the number of lenses and the type oflenses in the lens unit 115 may be adjusted in accordance with specificrequirements.

As shown in FIG. 2, the adjusting unit 116 is can be a stepper motor, avoice coil motor, or other motive element. The adjusting unit 116 isconnected to the lens unit 115 and configured to adjust distancesbetween the plurality of lenses of the lens unit 115, and then, changinga light spot density of a structured light pattern. When the distancebetween the two lenses is increased, a light spot density of astructured light pattern is also increased. Thereby, the light beams Boutput by the light spots generating unit 114 form a differentconcentration through the lens unit 115, that is, to change a spotdensity on a target area. In the embodiment, the adjusting unit 116 isconfigured to adjust a distance between the first convex lens L1 and theconcave lens L3, to ensure that the light beams B output by the lightspots generating unit 114 forms a different concentration through thelens unit 115.

Referring to FIGS. 3 and 4, the adjusting unit 116 drives the concavelens L3 to move away from the first convex lens L1 and closer to thesecond convex lens L2. At this time, a distance between the first convexlens L1 and the concave lens L3 is D1. The light beams B output by thelight spots generating unit 114 is received by the lens unit 115, andthe light beams B sequentially pass through the first convex lens L1,the concave lens L3, and the second convex lens L2, and then light beamsform a first light spot pattern T1. The first light spot pattern T1 isprojected to a target area by the lens unit 115.

Referring to FIGS. 3 and 5, the adjusting unit 116 continues to adjustthe concave lens L3 by driving the concave lens L3 further away from thefirst convex lens L1 and closer to the second convex lens L2. At thistime, a distance between the first convex lens L1 and the concave lensL3 is D2, and D2 is greater than D1. The light beams B output by thelight spots generating unit 114 are incident on the lens unit 115, andsequentially pass through the first convex lens L1, the concave lens L3,and the second convex lens L2, and then, the light beams forms a secondlight spot pattern T2. The second light spot pattern T2 is projected toa target area by the lens unit 115. As shown in FIGS. 4 and 5, the lightspot density of the second light spot pattern T2 is significantly largerthan the light spot density of the first light spot pattern T1. That is,when the distance between the first convex lens L1 and the concave lensL3 is gradually increased, the light beams output by the lens unit 115is more dense. That is, by adjusting the distance between the pluralityof lenses in the lens unit 115, the light spot density of the lightbeams projected to the target area can be effectively controlled, sothat the light spots are concentrated, or concentrated in a differentway, on the target object. In other embodiments, the adjusting unit 116may also adjust a distance between any two lenses to achieve the samepurpose.

Referring to FIG. 1 again, the microphone module 12 includes a pluralityof microphone units to receive any sound produced by a target object.The sound encoding module 13 is electrically connected to the microphonemodule 12 and the arithmetic unit 17. The sound encoding module 13 isconfigured to convert an analog sound received by the microphone module12 into a digital sound signal, and transmit the digital sound signal tothe arithmetic unit 17.

The rotation module 14 is included in the three-dimensional imagesensing device 100. The rotation module 14 rotates the optical projectormodule 11 within a specific angle. The rotation module 14 may be anyrotating mechanism that can control a rotation of the optical projectormodule 11. In one embodiment, the rotating mechanism comprising of atleast one motor and at least one gear driven by the motor.

The image acquisition module 15 may be a monochrome camera. The imageacquisition module 15 is electrically connected to the image processingunit 16. The image acquisition module 15 acquires a light spot image ofa target area when the light projection module 11 outputs the beamprojected to the target area, and transmits the light spot image to theimage processing unit 16.

The image processing unit 16 is electrically connected to the imageacquisition module 15. The image processing unit 16 receives the lightspot image acquired by the image acquisition module 15, performs imageanalysis and processing, determines whether a target object exists in atarget area, and outputs a corresponding signal to the arithmetic unit17 according to the determination. For example, when a target objectexists in the target area, the image processing unit 16 outputs a firstsignal to the arithmetic unit 17. When a target object does not exist inthe target area, the image processing unit 16 outputs a second signal tothe arithmetic unit 17.

In the embodiment, when a target object exists in a target area, theimage processing unit 16 is further configured to calculate a distancebetween the three-dimensional image sensing device 100 and the targetobject. An area of the target object is also calculated, as is arelative position of the target object in the spot image, and a depthinformation of the target object according to the received spot image.

In the embodiment, the first signal at least includes the distance, thearea, the relative position, and the depth information.

The arithmetic unit 17 may be a central processing unit (CPU) or anyarithmetic circuit with operational capability. The arithmetic unit 17is electrically connected to the sound encoding module 13, the rotationmodule 14, the image processing unit 16, the light source 112, and theadjusting unit 116. The arithmetic unit 17 receives a digital soundsignal transmitted from the sound encoding module 13 and processes thedigital sound signal to determine a sound source direction. Thearithmetic unit 17 also outputs a first rotation signal according to thesound source direction, the first rotation signal rotates the rotationmodule 14 through a specific angle, and the optical projector module 11is thus turned to the sound source direction.

When the arithmetic unit 17 receives the first signal from the imageprocessing unit 16, it is indicated that a target object exists in atarget area. The first signal includes at least one from the distance,the area, the relative position, and the depth information, or all ofthem. Meanwhile, the arithmetic unit 17 outputs a second rotation signalto the rotation module 14 according to the relative position, to controlthe rotation of the rotation module 14, and then fine-tune the directionof the optical projector module 11, so that the optical projector module11 is accurately directed toward the target object. Simultaneously, thearithmetic unit 17 also outputs a signal to the brake unit 116 accordingto the distance between the three-dimensional image sensing device 100and the target object, and further controls the adjusting unit 116 toadjust the distance between the lenses in the lens unit 115, to adjustthe light spot density projected to the target area. The light spots canthus be concentrated to the target object, thereby, the imageacquisition module 15 can accurately capture image of the second lightspots, and further establish the depth information of the target object.

When the arithmetic unit 17 receives a second signal from the imageprocessing unit 16, it is indicated that there is no target objectwithin the target area. At this time, the arithmetic unit 17 is furtherconfigured to output a third rotation signal, thereby controlling theoptical projector module 11 to rotate a preset angle. The light source112 of the optical projector module 11 begins to perform a secondprojection to continue to find the target object within a new targetarea.

Referring to FIG. 6, the light source 112 includes a plurality of pointlight sources D. The light sources D are arranged on the printed circuitboard 111 to emit a plurality of light beams. The plurality of pointlight sources D can a form circular shape, a diamond shape, square, or atriangle shape. The plurality of point light sources D forms a lightspot array A. The light spot array A can be divided into a plurality ofsub-arrays, such as sub-arrays A1, A2, A3, and A4, each sub-array beingindependently controlled. When the image processing unit 16 determinesthat a target object does not exist in a target area, the arithmeticunit 17 is further configured to control turning on and off of the lightsource 112, to adjust a number of light spots projected by the opticalprojector module 11, and then continue to find the target object.

For example, when the optical projector module 11 first projects lightspots, the arithmetic unit 17 only controls a part of light sources 112to turn on, for example, only the sub-array A1 of the point light sourceD is turned on, so that only the sub-array A1 emits light beams, theother sub-arrays do not emit light beams (see FIG. 6). Referring to FIG.7, when a target object is not found in the target area, the arithmeticunit 17 may control a certain number of light sources 112 to be turnedon, for example, the point light sources of the sub-arrays A1, A2 areturned on, and the sub-arrays A1, A2 emit light beams. By increasing thenumber of light spots projected by the optical projector module 11 byincreasing the emission beam of the light sources 112, the light spotprojection range can be effectively enlarged, and finding a targetobject in a new target area becomes easier.

In other embodiment, when a target object exists in the target area, thearithmetic unit 17 may also control and adjust the number of light spotsprojected by the optical projector module 11 according to the area ofthe target object. For example, when the area of the target object isless than a preset area, the arithmetic unit 17 is configured to reducethe number of light spots projected by the optical projector module 11such that only the point light sources D of the sub-arrays A1 are turnedon, as shown in FIG. 6. When the area of the target object is largerthan the preset area, the arithmetic unit 17 can increase the number oflight spots projected by the optical projector module 11, for example,the point light sources D of the sub-arrays A1, A2 are turned on, asshown in FIG. 7. This ensures that the light spots projected by theoptical projector module 11 completely cover the target object, therebyensuring the accuracy and the completeness of the image acquisition ofthe target object.

In other embodiments, the image processing unit 16 may be integrated inthe arithmetic unit 17, to achieve the same purpose as described above.

The memory unit 18 is electrically connected to the arithmetic unit 17for storing functional modules running in the three-dimensional imagesensing device 100, and various parameters of the three-dimensionalimage sensing device 100. The memory unit 18 is also configured to storeimage data for facilitating the image processing unit 16 or thearithmetic unit 17 to compare the spot image acquired by the imageacquisition module 15 with images pre-stored in the image database.

Referring again to FIG. 1, the three-dimensional image sensing apparatus100 further includes a wireless communication module 19. The wirelesscommunication module 19 is connected to the arithmetic unit 17 fortransmitting and receiving a wireless communication signal. Thethree-dimensional image sensing apparatus 100 is configured to transmitdata to a network server 300 to process and analyze via the wirelesscommunication module 19. The data can be light spot images captured bythe image acquisition module 15. The apparatus 100 also receives theresult of analysis from the network server 300 and governs thearithmetic unit 17 to perform a corresponding function.

In the embodiment, the three-dimensional image sensing apparatus 100 andthe network server 300 together form a three-dimensional image sensingsystem 500 for sensing and analyzing the three-dimensional image depthinformation, as shown in FIG. 1.

Referring to FIG. 8, the three-dimensional image sensing device 100further includes a housing 20. The housing 20 includes an upper housing201 and a lower housing 203. In the embodiment, the rotation module 14is disposed in the housing 20 and configured to drive the upper housing201 and the lower housing 203 to rotate relative to each other. Theoptical projector module 11 is provided in the upper housing 201. Whenthe rotation module 14 drives the upper housing 201 and the lowerhousing 203 to rotate relative to each other, the rotation of theoptical projector module 11 is driven in synchronization.

In the embodiment, the housing 20, such as the upper housing 201, isprovided with a plurality of microphone through-holes 205. Themicrophone module 12 is disposed within the housing 20 to receive soundthrough the microphone through-holes 205.

In the embodiment, the three-dimensional image sensing apparatus 100 isfurther provided with a light exiting hole 206 and a light entrance hole207. The light exiting hole 206 is aligned to the optical projectormodule 11, and light beams projected from the optical projector module11 are incident on an object O through the light exiting hole 206. Thelight entrance hole 207 is disposed to correspond to theimage-acquisition module 15, and the image acquisition module 15 isconfigured to receive a light spot image through the light entrance hole207.

FIGS. 9 and 10 illustrate a three-dimensional sensing method for thethree-dimensional image sensing device 100 according to one embodimentof the present application. The sensing method is provided by way ofexample as there are a variety of ways to carry out the method. Themethod 1 can begin at Step S100.

Step S100: the microphone module 12 is activated to receive a sound, thesound is produced by a target object.

Step S101: the sound is processed to determine a sound source direction,and the optical projector module 11 is controlled to rotate to towardthe sound source direction.

Step S102, referring to FIG. 11, the optical projector module 11 isturned on, and the optical projector module 11 projects a light spotpattern T1 with a specific density to a target area.

Step S103: a light spot image of the light spot pattern T1 to the targetarea is acquired.

Step S104, a light spot image of the light spot pattern T1 is subjectedto an image analysis and process to determine whether a target object Oexists in the target area. When the target object O exists in the targetarea, step S105 is executed. When the target object O does not exist inthe target area, step S111 is executed.

Step S105: When the target object O exists in the target area, theoptical projector module 11 is controlled to rotate according to arelative position of the target object O in the light spot image of thelight spot pattern T1 to fine tune the direction of the opticalprojector module 11, and the optical projector module 11 is orientedexactly towards the target object O.

Step S106: a distance between the three-dimensional image sensing device100 and the target object O and an area of the target object O arecalculated, respectively.

Step S107: the distance between the lenses in the lens unit 115 isadjusted according to the distance between the three-dimensional imagesensing device 100 and the target object O.

Step S108: The optical projector module 11 is turned on to perform asecond projection. As shown in FIG. 12, when the distance between thelenses in the lens unit 115 is adjusted and the optical projector module11 is subjected to a second projection, the density of the light spotsto the target area can be effectively controlled and adjusted, so thatthe light spots are concentrated to the target object O, so that theimage acquisition module 15 accurately captures a light point image ofthe second light spot pattern T2, and further to obtain a depthinformation of the target object O.

In step S108, the number of light spots projected by the opticalprojector module 11 may also be controlled according to an area of thetarget object O. For example, when the area of the target object O isless than a preset area, the number of light spots projected by theoptical projector module 11 may be appropriately reduced. When the areaof the target object O is larger than the preset area, the number oflight spots projected by the optical projector module 11 can beappropriately increased. This ensures that the light spots projected bythe optical projector module 11 covers the target object O morecompletely, and further ensures an accuracy and the completeness of theimage acquisition of the target object.

Step S109: a light spot image of the light spot pattern T2 on the targetarea is acquired, and the light spot image is processed and analyzed toobtain the depth information of the target object O. The light spotdensity of the light spot pattern T2 is greater than a light spotdensity of the light spot pattern T1.

Step S110: functions are performed according to the depth information ofthe target object O. In one embodiment, the three-dimensional imagesensing apparatus 100 may recognize the designated user according to thedepth information of the target object O and authorize the user. Thatis, the user is allowed to operate the three-dimensional image sensingdevice 100 to allow the user to operate other electronic devices throughthe three-dimensional image sensing device 100.

Step S111: when the image processing unit 16 determines that a targetobject does not exist in a target area, the optical projector module 11is controlled to rotate to adjust the direction of the optical projectormodule 11, and return to step S102. That is, the optical projectormodule 11 is turned on again so that the optical projector module 11projects a light spot pattern T1 with a specific density to a new targetarea, and then searches for the target object O in the new target area.That is, the optical projector module 11 of the 3D image sensing device100 is first configured to find the target object through a firstprojection. When the target object is found, the optical projectormodule 11 is controlled to perform a second projection and the lightspot density of the second projection is adjusted, so that the secondprojection can be accurately positioned to the target object. Theoptical projection module 11 performs a rough scan of the target objectwith a certain light spot density at a first projection, and thenexecutes a second projection with fine sweep to the target object whenfinding the target object, for changing the light spot density. Thus, apower consumption of the three-dimensional image sensing device 100 canbe saved effectively, which is more practical and convenient.

The embodiments shown and described above are only examples. Therefore,many commonly-known features and details are neither shown nordescribed. Even though numerous characteristics and advantages of thepresent technology have been set forth in the foregoing description,together with details of the structure and function of the presentdisclosure, the disclosure is illustrative only, and changes may be madein the detail, including in matters of shape, size, and arrangement ofthe parts within the principles of the present disclosure, up to andincluding the full extent established by the broad general meaning ofthe terms used in the claims. It will, therefore, be appreciated thatthe embodiments described above may be modified within the scope of theclaims.

What is claimed is:
 1. An optical projector module comprising: a printedcircuit board; a plurality of point light sources mounted on the printedcircuit board to emit a plurality of light beams; a lens unit positionedapart from the plurality of point light sources, wherein the lens unitcomprises a plurality of lenses spacing apart from each other; and anadjusting unit connecting to the lens unit, the adjusting unit beingconfigured to adjust distances between the plurality of lenses of thelens unit such that light beams with a first light spot pattern andlight beams with a second light spot pattern are respectively projectedto a target area, and a light spot density of the second light spotpattern is larger than a light spot density of the first light spotpattern.
 2. The optical projector module of claim 1, further comprisingan optical member, wherein the optical member is disposed in a lightpath of the plurality of point light sources, and configured to receiveand collimate the light beams.
 3. The optical projector module of claim2, further comprising a light spots generating unit, wherein the lightspots generating unit is positioned between the optical member and thelens unit, and is configured to expand the light beams from the opticalmember.
 4. The optical projector module of claim 3, wherein: the pointlight source is a vertical cavity surface-emitting laser.
 5. The opticalprojector module of claim 4, wherein: the plurality of point lightsources form a light spot array, the light spot array is divided into aplurality of sub-arrays, and each of the plurality of sub-arrays isindependently controlled.
 6. The optical projector module of claim 3,wherein: the plurality of lenses comprises a first convex lens, a secondconvex lens, and a concave lens, the first convex lens is disposedadjacent to the light spots generating unit, and the second convex lensis disposed on one side of the first convex lens away from the lightspots generating unit, the concave lens is disposed between the firstconvex lens and the second convex lens, and the adjusting unit isconfigured to adjust a distance between the first convex lens and theconcave lens.
 7. A three-dimensional image sensing apparatus comprising:an optical projector module, comprising: a printed circuit board; aplurality of point light sources mounted on the printed circuit board toemit a plurality of light beams; a lens unit positioned apart from theplurality of point light sources, wherein the lens unit comprises aplurality of lenses spacing apart from each other; and an adjusting unitconnecting to the lens unit, the adjusting unit being configured toadjust distances between the plurality of lenses of the lens unit suchthat light beams with a first light spot pattern and light beams with asecond light spot pattern are respectively projected to a target area,and a light spot density of the second light spot pattern is larger thana light spot density of the first light spot pattern; an imageacquisition module being electrically connected to the optical projectormodule and configured to acquire an image of the first light spotpattern on the target area; an arithmetic unit being electricallyconnected to the image acquisition module and configured to receive theimage of the first light spot pattern and determine whether a targetobject exists in the target area according to the received image,wherein when it is determined that the target object exists in thetarget area, the arithmetic unit controls the optical projector moduleto project the second light spot pattern to the target object.
 8. Thethree-dimensional image sensing apparatus of claim 7, further comprisinga microphone module and a rotation module, wherein the arithmetic unitis electrically connected to the microphone module and the rotationmodule, the microphone module is configured to receive a sound producedby the target object and transmit the sound signal to the arithmeticunit, the arithmetic unit is further configured to receive the soundsignal, determine a direction of the sound source according to the soundand output a rotation signal, and the rotation module is configured tocontrol the optical projector module to rotate toward the sound sourcedirection according to the rotation signal.
 9. The three-dimensionalimage sensing apparatus of claim 7, further comprising an imageprocessing unit, wherein the image processing unit is electricallyconnected to the image acquisition module and configured to receive theimage of the first light spot pattern acquired by the image acquisitionmodule, perform image analysis and processing, determine whether thetarget object exists in the target area, and output a correspondingsignal to the arithmetic unit.
 10. The three-dimensional image sensingapparatus of claim 9, further comprising a housing, wherein the housingcomprises an upper housing and a lower housing, and the rotation moduleis disposed in the housing and configured to drive the upper housing andthe lower housing to rotate relative to each other.
 11. Thethree-dimensional image sensing apparatus of claim 7, further comprisingan optical member, wherein the optical member is disposed in a lightpath of the point light sources for receiving and collimating lightbeams.
 12. The three-dimensional image sensing apparatus of claim 11,further comprising a light spots generating unit, wherein the lightspots generating unit is positioned between the optical member and thelens unit and confgiured to expand light beams from the optical member.13. The three-dimensional image sensing apparatus of claim 12, whereinthe point light source is a vertical cavity surface-emitting laser. 14.The three-dimensional image sensing apparatus of claim 13, wherein theplurality of point light sources form a light spot array, the light spotarray is divided into a plurality of sub-arrays, and each of theplurality of sub-arrays is independently controlled.
 15. Thethree-dimensional image sensing apparatus of claim 14, wherein theplurality of lenses comprises a first convex lens, a second convex lens,and a concave lens, the first convex lens is disposed adjacent to thelight spots generating unit, and the second convex lens is disposed onone side of the first convex lens away from the light spots generatingunit, the concave lens is disposed between the first convex lens and thesecond convex lens, and the adjusting unit is configured to adjust adistance between the first convex lens and the concave lens.
 16. Asensing method for a three-dimensional image comprising: projectinglight beams with a first light spot pattern to a target area by anoptical projector module; acquiring an image of the first light spotpattern on the target area; determining whether a target object existsin the target area according to the image; and controlling the opticalprojector module to rotate toward the target object, and projecting asecond light spot pattern to the target area when the target objectexists in the target area, wherein a light spot density of the secondlight spot pattern is larger than a light spot density of the firstlight spot pattern.
 17. The sensing method of claim 16, furthercomprising: receiving a sound signal and determining a direction of thesound signal; and outputting a rotation signal according to thedirection of the sound signal to control the optical projector module torotate toward the direction of the sound signal.
 18. The sensing methodof claim 17, further comprising: controlling the optical projectormodule to rotate to adjust a projection direction of a first light spotpattern when the target object dose not exist in the target area. 19.The sensing method of claim 18, further comprising: acquiring an imageof a second light spot pattern on the target area, analyzing andprocessing the image to obtain a depth information of the target object.